The Helicobacter pylori eradication in the group receiving standard -dose and group continue taking amoxicillin for 4 weeks; a clinical trial study.

Aim: The aim of this study was to evaluate the Helicobacter pylori eradication in the group receiving standard -dose twice a day for two weeks and continue taking amoxicillin for 4 weeks. Background: Helicobacter pylori is the major etiological cause of chronic gastritis, gastric and duodenal ulcers, gastric cancer and lymphoma. Therefore, patients should be treated after diagnosis of H. pylori infection. Patients and methods: A total of 66 consecutive patients with rapid urease test during endoscopy or biopsy positive for H. pylori were enrolled in this clinical trial study during 2013-2014. Patients were divided randomly into two groups. Group A (standard dose) received omeprazole (20 mg), amoxicillin (1 g), and clarithromycin (500 mg), all two times a day for two weeks. Group B received standard dose like group A and in patients with H.pylori infection amoxicillin were continued for 4 weeks. After completion of treatment, patients did not receive any treatment for a month and then stool antigen was performed to evaluate the H.pylori. Results: The rate of successful HP eradication was significantly higher in group A (90.9% V.s 63.6%; p=0.017). Inflation and bitter mouth were found in 8 and 13 patients in group A and 7 and 9 patients in group B, respectively. The incidence of adverse effects was the same (p=0.437). Conclusion: Increased duration of antibiotic therapy to four weeks significantly raises the rate of successful HP eradication with standard triple therapy without significant increase in adverse effects.

In recent year's eradication of HP infection in some cases were failed due to increasing resistance to clarithromycin and metronidazole (1)(2)(3). In different clinical trials, 61 to 93% eradication rate of H. pylori has been reported using two, three and four drugs regimes, whereas in the placebo-control studies eradication rate of H. pylori has been shown in 64-69% of cases using two-and three-drug regimen. In this study, the eradication rate of H. pylori in the two groups, including group A receiving the standard regimen and group B received standard dose like group A and in patients with H.pylori infection amoxicillin were continued for 4 weeks were evaluated.

Patients and Methods
In this clinical trial, patients with Helicobacter pylori infection during the period of 2013-14were recruited the study. Inclusion criteria, ,were including stopping using bismuth or antibiotics within 4 weeks before entry the study, no history of eradication of H.pylori or gastric cancer in the endoscopy report, no history of allergy to amoxicillin and omeprazole, no previous gastric surgery.
Invasive tests and/or rapid urease test were the first to be used in the diagnosis of H. pylori infection.
Then the data of the infected patients were recorded during endoscopy.
Following ethical and research committee approval, subjects gave their informed consent and was recruited into this study. Then the data of patients were collected using a valid questionnaire and divided randomly into two groups. For group A, a standard triple therapy for 2 weeks and then continued with 1000 mg amoxicillin every 12 hours for the next 2 weeks were administered. For group B, standard triple therapy for 2 weeks and then continued placebo every 12 hours for the next two weeks were administered.
It should be noted that omeprazole/amoxicillin/clarithromycin (Rx) every 12 hours was considered as the standard regimen in this study. After completion of treatment, patients did not receive any treatment for a month and then H.pylori stool antigen test was evaluated. Patients with drug intolerance were excluded. Finally, data regarding H. pylori eradication after treatment were collected and compared between the two groups. It should be noted that in order to reduce bias in the study, lab technicians were blind to the duration of treatment, dose of the drugs and type of regimen.

Statistical analysis
In this study, non-probability convenience sampling was used. To compare quantitative data between the two groups, independent samples ttest and for qualitative data Fisher's exact test or chi-square test were used. Statistical analyzes were performed using the SPSS software ver.16 and P<0.05 was considered as significant.

Results
Out of 80 patients, 14 patients found it hard and difficult to continue and subsequently were withdrawn from study and eventually study was conducted on 66 patients in the two groups. The mean age of patients in group A was 44.6 ± 14.9 years (range 23-77) and in group B was 41.8 ± 14.6 years (range 17-78). The difference between the two groups was not statistically significant (p=0.39). In the group A, 18 cases were men and in the placebo group, 16 were male. Distribution of comorbidities, the main complaint, smoking status and endoscopic findings of patients in both groups were presented in Table 1 and show that there is no significant difference between the two groups (p>0.05).
According to the study, we found that HP infection was successfully eradicated in 30 patients (90.9%) and 21 (63.6%) in group A and group B respectively. In this case, the difference between the two groups was statistically significant (p=0.01).
The only treatment-related side effect seen in the most of patients were bloating and bitter mouth. The incidence of these side effects was similar in the two groups (p=0.437). The main complaint of patients in both groups was epigastric pain, which is presented in 23 and 21 subjects in group A and B respectively. In both groups, the most common endoscopic findings were gastritis.

Discussion
The result of this study showed that increase the duration of amoxicillin usage is significantly associated with an increase in the success rate of HP infection eradication. In addition, we found that this method is a safe method and treatmentrelated side effects are as similar as common methods of treatment. Eradication of HP infection is one of the fundamental challenges in GI science. Omeprazole, clarithromycin and amoxicillin regimens are widely used for HP eradication due to high efficacy and limited side effects (28,39). On the other hand due to unsuccessful treatment of HP infection, researchers recommended the newer therapies such as quadruple therapy. There are several factors that can affect the success rate of HP eradication. One of the most important factors is the increasing antibiotic resistance, which raised these days and knowledge of the antibiotic resistance pattern can greatly assist in providing the most appropriate treatment strategy (40)(41)(42). It is very difficult to determine and assess the resistance of HP regularly, because the concentration of the antibiotic should be considered in gastric mucosal not in the blood (40).
Some researchers believe that in spite of using the same treatment regimens with Western countries, the success rate of HP infection eradication is much lower and therefore, the recurrence rate is much higher (43). To control the HP resistance, some researchers suggested increasing the duration of antibiotic treatment.
For instance, Fallone et al. recommended duration of proton pump inhibitor triple therapy should be increased from seven to 14 days (44). They concluded that an increased duration of treatment with triple therapy with PPI could significantly increase the success rate of HP eradication without being accompanied by an increased incidence of side effects. Also, Greenberg et al. performed randomized trial of experimental 14-day triple, 5-day concomitant, and 10-day sequential therapies for H. pylori eradication (45). The result of their trial showed that standard two-week triple-drug therapy is more effective than 5-day concomitant or 10-day sequential four-drug regimens as an experimental therapy for H pylori infection. Iwańczak suggested that to obtain better results of the eradication, the treatment should be prolonged from 7 to 10 or even 14 days, and it is necessary to increase the dose of antibiotics (46). However, despite these studies, Yoon and colleagues demonstrated that an increased duration of treatment did not increase the success of HP eradication due to the rapid increase in bacterial resistance. (47) In the present study, we examined the effect of increasing treatment duration from 14 to 28 days, and success rate of HP eradication. We have observed that increasing the duration of treatment was associated with a significantly increased HP eradication and as a result, successful treatment was detected in approximately 90% of patients in group-A. However, the high percentage of patients with placebo failed to treatment (36.4%) and this may indicate that the increased efficiency of antibiotic therapy is associated with an increased success rate of HP eradication. These findings are in accordance with previous studies that suggest prolonged antibiotic therapy can play an important role in increasing the success rate of HP eradication. This is an effective treatment and has been recommended by authors.